Thank you for your advice. It seems as though there are two camps of thought. One that sticks with Canon or aspires to carrying their glass and the other who are satisfied with the other brands.
Do you think that Sigma is superior to the other "non-Canon" brands? The other thing that makes me curious is that there seems to be from posts here and other sites like fredmiranda.com a higher "failure" rate among non-Canon lenses. My fear is that being a newbie to dSLR's I might not recognize anything short of a major defect in a lense